tee: add OP-TEE driver

Adds a OP-TEE driver which also can be compiled as a loadable module.

* Targets ARM and ARM64
* Supports using reserved memory from OP-TEE as shared memory
* Probes OP-TEE version using SMCs
* Accepts requests on privileged and unprivileged device
* Uses OPTEE message protocol version 2 to communicate with secure world

Acked-by: Andreas Dannenberg <dannenberg@ti.com>
Tested-by: Jerome Forissier <jerome.forissier@linaro.org> (HiKey)
Tested-by: Volodymyr Babchuk <vlad.babchuk@gmail.com> (RCAR H3)
Tested-by: Scott Branden <scott.branden@broadcom.com>
Reviewed-by: Javier González <javier@javigon.com>
Signed-off-by: Jens Wiklander <jens.wiklander@linaro.org>

1 files changed, 444 insertions, 0 deletions

diff --git a/drivers/tee/optee/call.c b/drivers/tee/optee/call.c
new file mode 100644
index 000000000000..f7b7b404c990
--- /dev/null
+++ b/drivers/tee/optee/call.c
@@ -0,0 +1,444 @@
+/*
+ * Copyright (c) 2015, Linaro Limited
+ *
+ * This software is licensed under the terms of the GNU General Public
+ * License version 2, as published by the Free Software Foundation, and
+ * may be copied, distributed, and modified under those terms.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ */
+#include <linux/arm-smccc.h>
+#include <linux/device.h>
+#include <linux/err.h>
+#include <linux/errno.h>
+#include <linux/slab.h>
+#include <linux/tee_drv.h>
+#include <linux/types.h>
+#include <linux/uaccess.h>
+#include "optee_private.h"
+#include "optee_smc.h"
+
+struct optee_call_waiter {
+	struct list_head list_node;
+	struct completion c;
+};
+
+static void optee_cq_wait_init(struct optee_call_queue *cq,
+			       struct optee_call_waiter *w)
+{
+	/*
+	 * We're preparing to make a call to secure world. In case we can't
+	 * allocate a thread in secure world we'll end up waiting in
+	 * optee_cq_wait_for_completion().
+	 *
+	 * Normally if there's no contention in secure world the call will
+	 * complete and we can cleanup directly with optee_cq_wait_final().
+	 */
+	mutex_lock(&cq->mutex);
+
+	/*
+	 * We add ourselves to the queue, but we don't wait. This
+	 * guarantees that we don't lose a completion if secure world
+	 * returns busy and another thread just exited and try to complete
+	 * someone.
+	 */
+	init_completion(&w->c);
+	list_add_tail(&w->list_node, &cq->waiters);
+
+	mutex_unlock(&cq->mutex);
+}
+
+static void optee_cq_wait_for_completion(struct optee_call_queue *cq,
+					 struct optee_call_waiter *w)
+{
+	wait_for_completion(&w->c);
+
+	mutex_lock(&cq->mutex);
+
+	/* Move to end of list to get out of the way for other waiters */
+	list_del(&w->list_node);
+	reinit_completion(&w->c);
+	list_add_tail(&w->list_node, &cq->waiters);
+
+	mutex_unlock(&cq->mutex);
+}
+
+static void optee_cq_complete_one(struct optee_call_queue *cq)
+{
+	struct optee_call_waiter *w;
+
+	list_for_each_entry(w, &cq->waiters, list_node) {
+		if (!completion_done(&w->c)) {
+			complete(&w->c);
+			break;
+		}
+	}
+}
+
+static void optee_cq_wait_final(struct optee_call_queue *cq,
+				struct optee_call_waiter *w)
+{
+	/*
+	 * We're done with the call to secure world. The thread in secure
+	 * world that was used for this call is now available for some
+	 * other task to use.
+	 */
+	mutex_lock(&cq->mutex);
+
+	/* Get out of the list */
+	list_del(&w->list_node);
+
+	/* Wake up one eventual waiting task */
+	optee_cq_complete_one(cq);
+
+	/*
+	 * If we're completed we've got a completion from another task that
+	 * was just done with its call to secure world. Since yet another
+	 * thread now is available in secure world wake up another eventual
+	 * waiting task.
+	 */
+	if (completion_done(&w->c))
+		optee_cq_complete_one(cq);
+
+	mutex_unlock(&cq->mutex);
+}
+
+/* Requires the filpstate mutex to be held */
+static struct optee_session *find_session(struct optee_context_data *ctxdata,
+					  u32 session_id)
+{
+	struct optee_session *sess;
+
+	list_for_each_entry(sess, &ctxdata->sess_list, list_node)
+		if (sess->session_id == session_id)
+			return sess;
+
+	return NULL;
+}
+
+/**
+ * optee_do_call_with_arg() - Do an SMC to OP-TEE in secure world
+ * @ctx:	calling context
+ * @parg:	physical address of message to pass to secure world
+ *
+ * Does and SMC to OP-TEE in secure world and handles eventual resulting
+ * Remote Procedure Calls (RPC) from OP-TEE.
+ *
+ * Returns return code from secure world, 0 is OK
+ */
+u32 optee_do_call_with_arg(struct tee_context *ctx, phys_addr_t parg)
+{
+	struct optee *optee = tee_get_drvdata(ctx->teedev);
+	struct optee_call_waiter w;
+	struct optee_rpc_param param = { };
+	u32 ret;
+
+	param.a0 = OPTEE_SMC_CALL_WITH_ARG;
+	reg_pair_from_64(&param.a1, &param.a2, parg);
+	/* Initialize waiter */
+	optee_cq_wait_init(&optee->call_queue, &w);
+	while (true) {
+		struct arm_smccc_res res;
+
+		optee->invoke_fn(param.a0, param.a1, param.a2, param.a3,
+				 param.a4, param.a5, param.a6, param.a7,
+				 &res);
+
+		if (res.a0 == OPTEE_SMC_RETURN_ETHREAD_LIMIT) {
+			/*
+			 * Out of threads in secure world, wait for a thread
+			 * become available.
+			 */
+			optee_cq_wait_for_completion(&optee->call_queue, &w);
+		} else if (OPTEE_SMC_RETURN_IS_RPC(res.a0)) {
+			param.a0 = res.a0;
+			param.a1 = res.a1;
+			param.a2 = res.a2;
+			param.a3 = res.a3;
+			optee_handle_rpc(ctx, &param);
+		} else {
+			ret = res.a0;
+			break;
+		}
+	}
+
+	/*
+	 * We're done with our thread in secure world, if there's any
+	 * thread waiters wake up one.
+	 */
+	optee_cq_wait_final(&optee->call_queue, &w);
+
+	return ret;
+}
+
+static struct tee_shm *get_msg_arg(struct tee_context *ctx, size_t num_params,
+				   struct optee_msg_arg **msg_arg,
+				   phys_addr_t *msg_parg)
+{
+	int rc;
+	struct tee_shm *shm;
+	struct optee_msg_arg *ma;
+
+	shm = tee_shm_alloc(ctx, OPTEE_MSG_GET_ARG_SIZE(num_params),
+			    TEE_SHM_MAPPED);
+	if (IS_ERR(shm))
+		return shm;
+
+	ma = tee_shm_get_va(shm, 0);
+	if (IS_ERR(ma)) {
+		rc = PTR_ERR(ma);
+		goto out;
+	}
+
+	rc = tee_shm_get_pa(shm, 0, msg_parg);
+	if (rc)
+		goto out;
+
+	memset(ma, 0, OPTEE_MSG_GET_ARG_SIZE(num_params));
+	ma->num_params = num_params;
+	*msg_arg = ma;
+out:
+	if (rc) {
+		tee_shm_free(shm);
+		return ERR_PTR(rc);
+	}
+
+	return shm;
+}
+
+int optee_open_session(struct tee_context *ctx,
+		       struct tee_ioctl_open_session_arg *arg,
+		       struct tee_param *param)
+{
+	struct optee_context_data *ctxdata = ctx->data;
+	int rc;
+	struct tee_shm *shm;
+	struct optee_msg_arg *msg_arg;
+	phys_addr_t msg_parg;
+	struct optee_session *sess = NULL;
+
+	/* +2 for the meta parameters added below */
+	shm = get_msg_arg(ctx, arg->num_params + 2, &msg_arg, &msg_parg);
+	if (IS_ERR(shm))
+		return PTR_ERR(shm);
+
+	msg_arg->cmd = OPTEE_MSG_CMD_OPEN_SESSION;
+	msg_arg->cancel_id = arg->cancel_id;
+
+	/*
+	 * Initialize and add the meta parameters needed when opening a
+	 * session.
+	 */
+	msg_arg->params[0].attr = OPTEE_MSG_ATTR_TYPE_VALUE_INPUT |
+				  OPTEE_MSG_ATTR_META;
+	msg_arg->params[1].attr = OPTEE_MSG_ATTR_TYPE_VALUE_INPUT |
+				  OPTEE_MSG_ATTR_META;
+	memcpy(&msg_arg->params[0].u.value, arg->uuid, sizeof(arg->uuid));
+	memcpy(&msg_arg->params[1].u.value, arg->uuid, sizeof(arg->clnt_uuid));
+	msg_arg->params[1].u.value.c = arg->clnt_login;
+
+	rc = optee_to_msg_param(msg_arg->params + 2, arg->num_params, param);
+	if (rc)
+		goto out;
+
+	sess = kzalloc(sizeof(*sess), GFP_KERNEL);
+	if (!sess) {
+		rc = -ENOMEM;
+		goto out;
+	}
+
+	if (optee_do_call_with_arg(ctx, msg_parg)) {
+		msg_arg->ret = TEEC_ERROR_COMMUNICATION;
+		msg_arg->ret_origin = TEEC_ORIGIN_COMMS;
+	}
+
+	if (msg_arg->ret == TEEC_SUCCESS) {
+		/* A new session has been created, add it to the list. */
+		sess->session_id = msg_arg->session;
+		mutex_lock(&ctxdata->mutex);
+		list_add(&sess->list_node, &ctxdata->sess_list);
+		mutex_unlock(&ctxdata->mutex);
+	} else {
+		kfree(sess);
+	}
+
+	if (optee_from_msg_param(param, arg->num_params, msg_arg->params + 2)) {
+		arg->ret = TEEC_ERROR_COMMUNICATION;
+		arg->ret_origin = TEEC_ORIGIN_COMMS;
+		/* Close session again to avoid leakage */
+		optee_close_session(ctx, msg_arg->session);
+	} else {
+		arg->session = msg_arg->session;
+		arg->ret = msg_arg->ret;
+		arg->ret_origin = msg_arg->ret_origin;
+	}
+out:
+	tee_shm_free(shm);
+
+	return rc;
+}
+
+int optee_close_session(struct tee_context *ctx, u32 session)
+{
+	struct optee_context_data *ctxdata = ctx->data;
+	struct tee_shm *shm;
+	struct optee_msg_arg *msg_arg;
+	phys_addr_t msg_parg;
+	struct optee_session *sess;
+
+	/* Check that the session is valid and remove it from the list */
+	mutex_lock(&ctxdata->mutex);
+	sess = find_session(ctxdata, session);
+	if (sess)
+		list_del(&sess->list_node);
+	mutex_unlock(&ctxdata->mutex);
+	if (!sess)
+		return -EINVAL;
+	kfree(sess);
+
+	shm = get_msg_arg(ctx, 0, &msg_arg, &msg_parg);
+	if (IS_ERR(shm))
+		return PTR_ERR(shm);
+
+	msg_arg->cmd = OPTEE_MSG_CMD_CLOSE_SESSION;
+	msg_arg->session = session;
+	optee_do_call_with_arg(ctx, msg_parg);
+
+	tee_shm_free(shm);
+	return 0;
+}
+
+int optee_invoke_func(struct tee_context *ctx, struct tee_ioctl_invoke_arg *arg,
+		      struct tee_param *param)
+{
+	struct optee_context_data *ctxdata = ctx->data;
+	struct tee_shm *shm;
+	struct optee_msg_arg *msg_arg;
+	phys_addr_t msg_parg;
+	struct optee_session *sess;
+	int rc;
+
+	/* Check that the session is valid */
+	mutex_lock(&ctxdata->mutex);
+	sess = find_session(ctxdata, arg->session);
+	mutex_unlock(&ctxdata->mutex);
+	if (!sess)
+		return -EINVAL;
+
+	shm = get_msg_arg(ctx, arg->num_params, &msg_arg, &msg_parg);
+	if (IS_ERR(shm))
+		return PTR_ERR(shm);
+	msg_arg->cmd = OPTEE_MSG_CMD_INVOKE_COMMAND;
+	msg_arg->func = arg->func;
+	msg_arg->session = arg->session;
+	msg_arg->cancel_id = arg->cancel_id;
+
+	rc = optee_to_msg_param(msg_arg->params, arg->num_params, param);
+	if (rc)
+		goto out;
+
+	if (optee_do_call_with_arg(ctx, msg_parg)) {
+		msg_arg->ret = TEEC_ERROR_COMMUNICATION;
+		msg_arg->ret_origin = TEEC_ORIGIN_COMMS;
+	}
+
+	if (optee_from_msg_param(param, arg->num_params, msg_arg->params)) {
+		msg_arg->ret = TEEC_ERROR_COMMUNICATION;
+		msg_arg->ret_origin = TEEC_ORIGIN_COMMS;
+	}
+
+	arg->ret = msg_arg->ret;
+	arg->ret_origin = msg_arg->ret_origin;
+out:
+	tee_shm_free(shm);
+	return rc;
+}
+
+int optee_cancel_req(struct tee_context *ctx, u32 cancel_id, u32 session)
+{
+	struct optee_context_data *ctxdata = ctx->data;
+	struct tee_shm *shm;
+	struct optee_msg_arg *msg_arg;
+	phys_addr_t msg_parg;
+	struct optee_session *sess;
+
+	/* Check that the session is valid */
+	mutex_lock(&ctxdata->mutex);
+	sess = find_session(ctxdata, session);
+	mutex_unlock(&ctxdata->mutex);
+	if (!sess)
+		return -EINVAL;
+
+	shm = get_msg_arg(ctx, 0, &msg_arg, &msg_parg);
+	if (IS_ERR(shm))
+		return PTR_ERR(shm);
+
+	msg_arg->cmd = OPTEE_MSG_CMD_CANCEL;
+	msg_arg->session = session;
+	msg_arg->cancel_id = cancel_id;
+	optee_do_call_with_arg(ctx, msg_parg);
+
+	tee_shm_free(shm);
+	return 0;
+}
+
+/**
+ * optee_enable_shm_cache() - Enables caching of some shared memory allocation
+ *			      in OP-TEE
+ * @optee:	main service struct
+ */
+void optee_enable_shm_cache(struct optee *optee)
+{
+	struct optee_call_waiter w;
+
+	/* We need to retry until secure world isn't busy. */
+	optee_cq_wait_init(&optee->call_queue, &w);
+	while (true) {
+		struct arm_smccc_res res;
+
+		optee->invoke_fn(OPTEE_SMC_ENABLE_SHM_CACHE, 0, 0, 0, 0, 0, 0,
+				 0, &res);
+		if (res.a0 == OPTEE_SMC_RETURN_OK)
+			break;
+		optee_cq_wait_for_completion(&optee->call_queue, &w);
+	}
+	optee_cq_wait_final(&optee->call_queue, &w);
+}
+
+/**
+ * optee_disable_shm_cache() - Disables caching of some shared memory allocation
+ *			      in OP-TEE
+ * @optee:	main service struct
+ */
+void optee_disable_shm_cache(struct optee *optee)
+{
+	struct optee_call_waiter w;
+
+	/* We need to retry until secure world isn't busy. */
+	optee_cq_wait_init(&optee->call_queue, &w);
+	while (true) {
+		union {
+			struct arm_smccc_res smccc;
+			struct optee_smc_disable_shm_cache_result result;
+		} res;
+
+		optee->invoke_fn(OPTEE_SMC_DISABLE_SHM_CACHE, 0, 0, 0, 0, 0, 0,
+				 0, &res.smccc);
+		if (res.result.status == OPTEE_SMC_RETURN_ENOTAVAIL)
+			break; /* All shm's freed */
+		if (res.result.status == OPTEE_SMC_RETURN_OK) {
+			struct tee_shm *shm;
+
+			shm = reg_pair_to_ptr(res.result.shm_upper32,
+					      res.result.shm_lower32);
+			tee_shm_free(shm);
+		} else {
+			optee_cq_wait_for_completion(&optee->call_queue, &w);
+		}
+	}
+	optee_cq_wait_final(&optee->call_queue, &w);
+}